Metabolic modulation of Basil (Ocimum basilicum L.): an insight into growth, metabolomics and antioxidant activity under varying temperature and light conditions

Background Temperature and light are two critical environmental stimuli that greatly impact our agricultural industry. We explored the effects of varying temperature and light conditions on the metabolomics of basil, a plant widely used in cuisine and for medicinal purposes worldwide. Basil plants were subjected to elevated temperatures of 30 degrees C, 35 degrees C, and 40 degrees C, along with two light intensities (D11 and D23).Results Our results showed that the maximum shoot length (42.98 cm) was achieved at T30 and D23, the maximum leaf area (6.92 cm) at T30/D11, and the highest number of leaves (472) at T40/D11. However, at the higher temperature of T40, the number of leaves increased, but shoot length and leaf size significantly decreased (p < 0.05). Maxim shoot biomass (81 gm) and root biomass (91.2 gm) was recorded at T35/D23 treatments. Metabolomic studies of basil revealed that rosmarinic acid (RA), and linalool and eugenol were the major phenolic and volatile organic compounds (VOCs) under different growth conditions. RA levels were higher at 30 degrees C, correlated with elevated shikimate levels, indicating a carbon supply through the TCA cycle. In contrast, the growth conditions of 35 degrees C/D11 (mu mol/m(2)/d) up-regulated the glyoxylate cycle (fumaric acid and malic acid) as part of stomatal closure, preventing ROS accumulation and resulting in increased VOC emission. Exposure to the higher temperature of 40 degrees C induced higher amino acid accumulation, improving temperature stresstolerance.Conclusions This study suggests that elevated temperature and light intensity affected the overall health of basil plants by modulating underlying growth mechanisms. Furthermore, elevated temperature plays a vital role in plant defense mechanisms by mediating the production of secondary metabolites associated with plant defense responses.